The Calymperaceae are closely allied with the Pottiaceae; no single character or combination of characters uniformly separates the two families (Reese & Zander 1988).

Only the genera traditionally assigned to the Calymperaceae—Calymperes, Mitthyridium (syn. Thyridium), and Syrrhopodon—are included in this treatment of the Chinese Calymperaceae. Mosses belonging to subgenus Pseudocalymperes (syn. Calymperopsis), which is sometimes recognized at the generic level, are here included in Syrrhopodon.

Plants small to robust, tufted to gregarious, usually growing on trees and logs, sometimes on rocks or soil. Stems mostly erect, but typically repent and with ascending-erect branches in Mitthyridium and rarely in Syrrhopodon, stems very short in some taxa and plants then with stemless appearance. Rhizoids mostly scanty, brown to red or dark red or purple. Leaves crowded, sheathing at base, axillary hairs mostly inconspicuous; leaf margins mostly thickened, often toothed, bordered with elongate hyaline cells in Mitthyridium and some Syrrhopodon, thickened border often enclosing stereid cells; costa strong, convex on back, often papillose or spinose on one or both sides, ending near apex to excurrent, frequently with clusters of gemmae at tip; cells of upper laminae green, mostly isodiametric, smooth to papillose; lower laminae including conspicuous (typically) fields of enlarged, internally and externally porose, hyaline cells (cancellinae); intramarginal files of differentiated cells (teniolae) present in leaves of some Calymperes and (rarely) Syrrhopodon; gemmiferous leaves often (sometimes strongly) differentiated from vegetative leaves; gemmae common, uniseriate, fusiform to clavate to filamentous, borne exclusively on leaves. Primarily dioicous, rarely monoicous. Perigonia axillary, bud-like; perichaetia terminal but soon overtopped. Perichaetial leaves reduced but otherwise not or only somewhat differentiated. Setae straight, mostly elongate but very short in some Syrrhopodon; capsules cylindric; annuli lacking; opercula rostrate; peristome lacking, or present and of 16 jointed smooth or papillose teeth, often reduced and imperfect. Calyptrae cucullate and deciduous, or enveloping the capsule, persistent, and opening by vertical slits, rarely very small and mitrate. Spores small, mostly roughened.

5. Stems mostly erect, lacking erect branches; leaf border of hyaline cells narrow, multistratose, sometimes more or less lacking along part of the margin on some or most leaves................................... 3. Syrrhopodon

6. Leaves with intramarginal files of differentiated cells (teniolae) at least at the shoulder region (teniolae difficult to see due to tuberculosities in Calymperes strictifolium)............................. 1. Calymperes p.p.